|
|
|
|
Compost Party (Greens and Browns) |
OBJECTIVES:
VOCABULARY:
MATERIALS:
BACKGROUND:
All
living organisms have a Carbon to Nitrogen (C:N) ratio for their tissues.
For microorganisms, carbon is
the basic building block of life and is a source of energy, but nitrogen
is also necessary for such things as proteins, genetic material, and cell
structure.
Decomposition of organic materials in your compost pile is greatly
increased when you create the proper balance between the carbonaceous
materials (called
BROWN
because they are dry) and the nitrogen-rich materials (called
GREEN
because they are more fresh and moist). This balance is referred to as the
Carbon-Nitrogen ratio,
and shown as C:N.
Microorganisms that digest compost need about 30 parts of carbon for every
part of nitrogen they consume. That's a balanced diet for them. If there's
too much nitrogen, the microorganisms can't use it all and the excess is
lost in the form of smelly ammonia gas. Nitrogen loss due to excess
nitrogen in the pile (a low C:N ratio) can be over 60%. At a C:N ratio of
30 or 35 to 1, only one half of one percent of the nitrogen will be lost.
That's why you don't want too much nitrogen (fresh manure, for example) in
your compost: the nitrogen will be lost in the air in the form of ammonia
gas, and nitrogen is too valuable for plants to allow it to escape into
the atmosphere.
5.
Generally speaking, you can get C:N ratios of 30:1 to 50:1 by adding two
parts of a GREEN material to one part of a BROWN material to your bin.
A "part" can be defined
as a certain quantity of the material, such as two 5-gallon buckets of
GREEN and 1 packed bucket of BROWN.
6.
Play with the chart below.
For example, food scraps, grass clippings and leaves come close to an
average of 30:1. How? Add-up the Carbon side of the ratio for all three
materials, i.e. 15, 17, 60, and divide by the number of materials, i.e.
three. 92/3 = about 31:1.
PROCEDURE: 1. Above information is just for teachers who want to understand more the complex nature of making good compost. Remember compost is just one component to make enriched soil. Soil is rocks plus organic matter. Compost is organic matter.2. Schedule a compost party. Send parents a notice of what you are doing (flyer). This helps increase their awareness of what experiment their students will be participating.
Types of food waste needed:
Do
not bring MILK
Products (cheese, yogurt, etc)
|